1. Field of Invention
Apparatuses and methods consistent with the present disclosure of invention relate to Liquid Crystal Display (LCD) devices and manufacturing methods therefor.
2. Description of Related Art
Generally, a liquid crystal display device is one of the most popular flat panel displays used for computer monitor applications and the like. An LCD device typically includes two display substrates formed as a sandwich with liquid crystal material interposed therebetween. Inwardly facing surfaces of the two display substrates have electric field generating electrodes disposed on them such as an array of pixel electrodes and a common electrode, and the liquid crystal material is inserted between the two display substrates. The liquid crystal material has a dielectric anisotropy characteristic that allows it to alter transmission of light therethrough as a function of an electric field applied across the material.
More specifically, the liquid crystal display device controls an alignment of liquid crystal molecules in the liquid crystal layer by supplying a control voltage between the field generating electrodes to thereby apply an electric field of desired intensity and/or polarity to the liquid crystal material to thereby effect a twisting of the liquid crystal material and to thus control polarization of light passing through the material, thereby displaying a desired image.
The twisted nematic (TN) type of liquid crystal material has been widely used. In the TN type of liquid crystal display, the field generating electrodes are disposed on the counterfacing inner surfaces of the two display substrates, respectively, and liquid crystal polarization directors are arranged in the device to encourage a normal twisting by 90° of light passing from the lower display substrate to the upper display substrate. This twisting in combination with polarization plates, prevents light from passing through, thus presenting a dark pixel area. Then, a twisting voltage is applied between the two field generating electrodes to change the normal liquid crystal polarization and allow light to pass through thus changing the dark pixel area into a lit one. However, the liquid crystal display device of this TN type tends to have a narrow viewing angle with poor image contrast when viewed from one side or another of the display rather than head on. Accordingly, a liquid crystal display of an IPS (in-plane switching) type or a PLS (plane to line switching) type has been developed as an alternative to the TN type.
However, in the conventional IPS type and the PLS type, since both of the two field generating electrodes are disposed on a single display substrate, light transmittance and image visibility become deteriorated.